Head lice are common but are really just a nuisance. Body lice, on the other hand, are less common, but are more dangerous because they can transmit diseases such as typhus, trench fever, and relapsing fever, Levine says. If you are bitten, you are likely to experience intense itching, have a rash, red bumps or thickened skin. Keep good hygiene and wash your clothes and bed linens often to prevent infestations.